DE19511516C1 - Hybrid drive for automobile - Google Patents

Abstract

The hybrid drive has a combustion engine (3) using methanol or hydrogen as the fuel, driving an electrical generator (2), coupled to a storage battery (4), with an electric drive motor (1), driven directly by the generator or via the battery. A hydrogen extraction device (7) is coupled to the fuel reservoir holding the methanol, for providing hydrogen via a reformation process, the engine supplied with methanol in the high load range and with hydrogen in the starting and warm running ranges.

Description

The invention relates to a hybrid drive according to the Preamble of claim 1 and a method for Operation of the same. Such drives are particularly in Motor vehicles used.

It is known that in hybrid drives of this construction, the heat Mekraft machine as a combustion engine for a hydrocarbon to design fuel containing fuel and if possible in a sta tionaries, opti with regard to the specific fuel consumption paint operating point to operate, possibly higher Power requirement due to the additionally provided energy storage cher is provided. The energy storage is in operation phases with less power requirement from that by Heat engine generated energy again loaded with energy the.

Such hybrid drives, in which in addition to an internal combustion engine machine usually one of these downstream generator and one Electric motor as the drive motor and a traction battery as Energy storage devices are provided, for example, in the Publications DE 41 33 013 A1, DE 43 31 569 A1 and WO 92/18346 and in the patent US 4,119,862. In addition to electrical energy transfer between thermal power machine and drive motor are also hybrid drives with hydraulic known energy transmission, see z. B. Disclosure document DE 35 01 608 A1.

A method is described in the published patent application DE 35 23 855 A1 to operate a free-sucking or charged internal combustion engine machine described, essentially with a methanol  generated, containing mainly hydrogen and carbon monoxide Fission gas and air is operated, which the methanol in one Gasification reactor utilizing that of the internal combustion engine ne exhaust gas heat emitted is gasified. For no additional The burner will need heating for the gasification reactor engine directly at start-up and during warm-up fed the methanol fuel, while warming up the methanol supply was successively reduced and the cracked gas supply is gradually increased accordingly. When using a Auto-ignition internal combustion engine is provided, the ignition the mixture of cracked gas and air using high pressure injection igniting an ignitable fuel, such as diesel fuel effect, why a separate storage container for the ignitable Fuel is arranged. The energy portion of the ignitable In normal operation the fuel is approx. 5% to 10%, whereby the This proportion can be increased if the exhaust heat of the Internal combustion engine no longer for complete methanol splitting is sufficient.

The invention is a technical problem of providing of a hybrid drive that works with low and medium drive Force requirements with activated thermal engine with gerin pollutant emissions can be operated and if necessary can provide additional drive power, as well as a method for the most effective and emission-free operation of the same.

This problem is caused by a hybrid drive with the features of claim 1 and by a method with the features of Claim 2 solved. The heat engine of this hybrid drive can optionally directly with the hydrocarbonaceous distillate be operated with hydrogen or hydrogen. The latter represents a particularly low-emission operation of thermal power machine. By making the hydrogen through a hydrogen gain Generating unit is generated, the hydrogen from the fed hydrogenated, hydrocarbon and hydrogen recovery If the fuel wins, no hydrogen storage is required  tigt, which is especially for use in motor vehicles Advantage is. Through the addition to the heat engine Supply of the drive motor provided energy storage, in the energy of the heat engine can be stored if required can, is very good on the respective drive load Tunable drive with the lowest possible pollutant emissions system provided. The cheap in this respect The method of claim 2 provides that the heat engine in a high performance range directly with the hydrocarbon containing fuel, in lower drive load ranges conditions with optimally low pollutant emissions from the obtained To operate hydrogen. Sufficient in this lower drive load range from the ar on this stationary operating point energy produced by the heat engine will not additional energy taken from the energy storage. The Refor mer unit therefore does not need to achieve very high what Gas recovery rates are interpreted and can therefore be dimension sufficiently small to also for mobile applications to be well suited. The energy storage is in operating phases recharged with very little power requirement. How usual with hybrid drives, can be especially with low An drive load request the heat engine is turned off and the Drive motor are fed solely from the energy storage, z. B. for emission-free city trips of a motor vehicle.

Another particular advantage of the system is that it is green det that that in conventional drives for emissions essentially responsible start and warm up here with water can be fuel operated. To do this, the following procedure must be followed hen:

The vehicle begins its journey purely electrically, powered by the traction battery. About a fossil additional burner, the works with the refueled fuel, or with energy from the Traction battery, the referrer is activated. If he is operating is ready and can produce hydrogen, the combustion engine started with this hydrogen and let it warm up. During the warm-up period, power can already be provided to the driver  drive can be removed. After warming up all are then wrote operating modes with methanol and / or hydrogen bar.

A preferred embodiment of the invention is in the drawing voltage and is described below.

The single figure shows a block diagram of a hybrid drive for a motor vehicle.

In the hybrid drive shown, an electric motor ( 1 ) is used to drive a motor vehicle schematically presented with its four wheels ( 5 ) Darge. The motor ( 1 ) drives the two wheels of a drive axle, alternatively a two-axle drive or several parallel electric motors can be provided for individual axles or wheels of the motor vehicle. The drive electric motor ( 1 ) is electrically connected on the one hand to a traction battery ( 4 ) and on the other hand to a generator ( 2 ) which is mechanically coupled to an internal combustion engine ( 3 ). The traction battery ( 4 ) is also closed to the generator ( 2 ), so that electrical energy, as indicated by the arrows, from the generator ( 2 ) on the one hand to the electric motor ( 1 ) and on the other hand to the traction battery ( 4 ) and from the traction battery ( 4 ) can be transmitted to the electric motor ( 1 ). For the transmission and conversion of the electrical energies, further components such as a rectifier connected downstream of the generator ( 2 ), an inverter connected upstream of the drive electric motor ( 1 ) and an electrical control device are used, which are of conventional design and can be easily implemented by a person skilled in the art depending on the application which is why they are not shown explicitly.

The operation of the internal combustion engine ( 3 ) takes place either with methanol or with hydrogen (H₂) as fuels, which can be fed to it via separate feed lines ( 8 , 9 ). The methanol is stored in liquid form in an associated methanol tank ( 6 ) of the motor vehicle. To provide the hydrogen, a reformer unit ( 7 ) is provided, which can be fed on the input side with the methanol from the storage tank ( 6 ) and in which the supplied methanol is subjected to a conventional reforming reaction. This reaction produces a gas mixture containing hydrogen, from which the hydrogen can be selectively separated by methods which are also known per se. The hydrogen gas obtained in this way is then fed by the reformer unit ( 7 ) into the corresponding feed line ( 9 ) for the internal combustion engine ( 3 ). As an alternative to the separate methanol feed shown, provision can be made to link the methanol line ( 8 ) branching off in front of the reformer unit ( 7 ) by means of a valve with the hydrogen line leading away from the reformer unit ( 7 ) and only one, for the internal combustion engine ( 3 ) Arrange valve outgoing supply line. By controlling this valve you can then switch between methanol injection and hydrogen injection. In the present, separate feed lines ( 8 , 9 ), this changeover takes place by actuating valves, not shown, which are respectively arranged in these lines.

The hybrid drive constructed in this way enables the following advantageous drive method for the motor vehicle. In Lei stungsbetrieb, ie in a high drive load range, the internal combustion engine ( 3 ) is operated directly with the methanol, where it can generate the required high power. The generator ( 2 ) converts the mechanical energy provided by the internal combustion engine ( 3 ) into electrical energy and supplies it to the drive electric motor ( 1 ). If necessary, further electrical energy can be supplied from the traction battery ( 4 ) to the drive electric motor ( 1 ). In the lower drive load range and when starting and warming up, the internal combustion engine ( 3 ) is operated with the hydrogen gas which the reformer unit ( 7 ) obtains from the methanol fuel. In this hydrogen gas operation, the internal combustion engine ( 3 ) is kept stationary at an optimal pollutant-minimizing operating point. If a higher drive power is requested during this operation, which is lower than in methanol-powered power operation of the internal combustion engine ( 3 ), but higher than the power generated by the latter in the stationary hydrogen-powered operating point, the traction battery ( 4 ) covers the remaining power requirement. In operating states with a lower required drive power, the traction battery ( 4 ) is then recharged with the excess energy not required for the drive of the internal combustion engine ( 3 ). In addition, the drive motor can be powered by the traction battery alone when the internal combustion engine is switched off in emission-free operating phases. It is understood that for the control of the various functions described, a suitable hybrid drive control, not shown, is provided which, in addition to the control functions known from conventional hybrid drives, also controls the fuel supply for the internal combustion engine ( 3 ) and the reforming unit ( 7 ) in the suitable way takes over. This control can be integrated in a Regelein direction with which the operation of the internal combustion engine ( 3 ) and the functions of the other drive components is regulated depending on the required drive power.

The hybrid drive shown consequently realizes a vehicle drive which is optimized with regard to pollutant emissions and can be flexibly adapted to different drive power requirements. It is understood that another fuel containing hydrocarbons can be used as fuel for the internal combustion engine ( 3 ) instead of methanol, from which hydrogen can be split off, for. B. ethanol or other alcohols. Depending on the fuel used, the hydrogen extraction unit is selected appropriately to generate the desired hydrogen gas. In addition to a normal piston internal combustion engine, a free piston engine or a Stirling engine can also be used as a heat engine. Instead of the electrical energy transmission system between the heat engine and the drive motor, a hydraulic or a pneumatic system can be used, the drive motor then being formed by a hydraulic or pneumatic motor. In addition to the traction battery mentioned, other conventional electrical or other storage media, for. B. a mechanical energy-storing flywheel storage.

Claims (3)

1. Hybrid drive, especially for a motor vehicle, with

• - A heat engine ( 3 ) which can be driven with a hydrocarbon-containing, hydrogen-recoverable fuel,
• - a store ( 6 ) for the hydrocarbon-containing, hydrogen-recoverable fuel,
• - An energy store ( 4 ), in which energy generated by the heat engine can be stored, and
• - A drive motor ( 1 ) which is fed as a function of the operating state and is powered by the energy of the heat engine and / or the energy store,

marked by

• - A hydrogen recovery unit ( 7 ), which is connected on the input side to the fuel storage ( 6 ) and wins hydrogen from the hydrocarbon-containing, hydrogen-recoverable fuel, wherein
• - The heat engine ( 3 ) is set up for operation either with the hydrocarbon-containing fuel that can be supplied from the store ( 6 ) or with the hydrogen obtained from the hydrogen recovery unit ( 7 ).

2. Method for operating a hybrid drive, in particular for a motor vehicle, characterized by the following features for operating the hybrid drive according to claim 1 in active operating phases of the heat engine ( 3 ):

• - In a higher drive load range, the heat engine ( 3 ) is actively operated with the hydrocarbon-containing, hydrogen-recoverable fuel and
• - In a lower drive load range and during start-up and warm-up, the heat engine is actively operated with the hydrogen obtained stationary on a low-polluting operating point, whereby
• - During operating phases in which the heat engine is operated with the hydrogen and the requested drive power is higher than the power generated by the heat engine operated on the stationary operating point, the remaining power requirement from the energy store ( 4 ) is provided.